Alright, let's solve this math problem step by step. First, we have the number 820. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 210. So, we're going to take the number 820 and add it to itself 210 times.
Step 1: 0 + 820 = 820
Step 2: 820 + 820 = 1640
Step 3: 1640 + 820 = 2460
Step 4: 2460 + 820 = 3280
Step 5: 3280 + 820 = 4100
Step 6: 4100 + 820 = 4920
Step 7: 4920 + 820 = 5740
Step 8: 5740 + 820 = 6560
Step 9: 6560 + 820 = 7380
Step 10: 7380 + 820 = 8200
Step 11: 8200 + 820 = 9020
Step 12: 9020 + 820 = 9840
Step 13: 9840 + 820 = 10660
Step 14: 10660 + 820 = 11480
Step 15: 11480 + 820 = 12300
Step 16: 12300 + 820 = 13120
Step 17: 13120 + 820 = 13940
Step 18: 13940 + 820 = 14760
Step 19: 14760 + 820 = 15580
Step 20: 15580 + 820 = 16400
Step 21: 16400 + 820 = 17220
Step 22: 17220 + 820 = 18040
Step 23: 18040 + 820 = 18860
Step 24: 18860 + 820 = 19680
Step 25: 19680 + 820 = 20500
Step 26: 20500 + 820 = 21320
Step 27: 21320 + 820 = 22140
Step 28: 22140 + 820 = 22960
Step 29: 22960 + 820 = 23780
Step 30: 23780 + 820 = 24600
Step 31: 24600 + 820 = 25420
Step 32: 25420 + 820 = 26240
Step 33: 26240 + 820 = 27060
Step 34: 27060 + 820 = 27880
Step 35: 27880 + 820 = 28700
Step 36: 28700 + 820 = 29520
Step 37: 29520 + 820 = 30340
Step 38: 30340 + 820 = 31160
Step 39: 31160 + 820 = 31980
Step 40: 31980 + 820 = 32800
Step 41: 32800 + 820 = 33620
Step 42: 33620 + 820 = 34440
Step 43: 34440 + 820 = 35260
Step 44: 35260 + 820 = 36080
Step 45: 36080 + 820 = 36900
Step 46: 36900 + 820 = 37720
Step 47: 37720 + 820 = 38540
Step 48: 38540 + 820 = 39360
Step 49: 39360 + 820 = 40180
Step 50: 40180 + 820 = 41000
Step 51: 41000 + 820 = 41820
Step 52: 41820 + 820 = 42640
Step 53: 42640 + 820 = 43460
Step 54: 43460 + 820 = 44280
Step 55: 44280 + 820 = 45100
Step 56: 45100 + 820 = 45920
Step 57: 45920 + 820 = 46740
Step 58: 46740 + 820 = 47560
Step 59: 47560 + 820 = 48380
Step 60: 48380 + 820 = 49200
Step 61: 49200 + 820 = 50020
Step 62: 50020 + 820 = 50840
Step 63: 50840 + 820 = 51660
Step 64: 51660 + 820 = 52480
Step 65: 52480 + 820 = 53300
Step 66: 53300 + 820 = 54120
Step 67: 54120 + 820 = 54940
Step 68: 54940 + 820 = 55760
Step 69: 55760 + 820 = 56580
Step 70: 56580 + 820 = 57400
Step 71: 57400 + 820 = 58220
Step 72: 58220 + 820 = 59040
Step 73: 59040 + 820 = 59860
Step 74: 59860 + 820 = 60680
Step 75: 60680 + 820 = 61500
Step 76: 61500 + 820 = 62320
Step 77: 62320 + 820 = 63140
Step 78: 63140 + 820 = 63960
Step 79: 63960 + 820 = 64780
Step 80: 64780 + 820 = 65600
Step 81: 65600 + 820 = 66420
Step 82: 66420 + 820 = 67240
Step 83: 67240 + 820 = 68060
Step 84: 68060 + 820 = 68880
Step 85: 68880 + 820 = 69700
Step 86: 69700 + 820 = 70520
Step 87: 70520 + 820 = 71340
Step 88: 71340 + 820 = 72160
Step 89: 72160 + 820 = 72980
Step 90: 72980 + 820 = 73800
Step 91: 73800 + 820 = 74620
Step 92: 74620 + 820 = 75440
Step 93: 75440 + 820 = 76260
Step 94: 76260 + 820 = 77080
Step 95: 77080 + 820 = 77900
Step 96: 77900 + 820 = 78720
Step 97: 78720 + 820 = 79540
Step 98: 79540 + 820 = 80360
Step 99: 80360 + 820 = 81180
Step 100: 81180 + 820 = 82000
Step 101: 82000 + 820 = 82820
Step 102: 82820 + 820 = 83640
Step 103: 83640 + 820 = 84460
Step 104: 84460 + 820 = 85280
Step 105: 85280 + 820 = 86100
Step 106: 86100 + 820 = 86920
Step 107: 86920 + 820 = 87740
Step 108: 87740 + 820 = 88560
Step 109: 88560 + 820 = 89380
Step 110: 89380 + 820 = 90200
Step 111: 90200 + 820 = 91020
Step 112: 91020 + 820 = 91840
Step 113: 91840 + 820 = 92660
Step 114: 92660 + 820 = 93480
Step 115: 93480 + 820 = 94300
Step 116: 94300 + 820 = 95120
Step 117: 95120 + 820 = 95940
Step 118: 95940 + 820 = 96760
Step 119: 96760 + 820 = 97580
Step 120: 97580 + 820 = 98400
Step 121: 98400 + 820 = 99220
Step 122: 99220 + 820 = 100040
Step 123: 100040 + 820 = 100860
Step 124: 100860 + 820 = 101680
Step 125: 101680 + 820 = 102500
Step 126: 102500 + 820 = 103320
Step 127: 103320 + 820 = 104140
Step 128: 104140 + 820 = 104960
Step 129: 104960 + 820 = 105780
Step 130: 105780 + 820 = 106600
Step 131: 106600 + 820 = 107420
Step 132: 107420 + 820 = 108240
Step 133: 108240 + 820 = 109060
Step 134: 109060 + 820 = 109880
Step 135: 109880 + 820 = 110700
Step 136: 110700 + 820 = 111520
Step 137: 111520 + 820 = 112340
Step 138: 112340 + 820 = 113160
Step 139: 113160 + 820 = 113980
Step 140: 113980 + 820 = 114800
Step 141: 114800 + 820 = 115620
Step 142: 115620 + 820 = 116440
Step 143: 116440 + 820 = 117260
Step 144: 117260 + 820 = 118080
Step 145: 118080 + 820 = 118900
Step 146: 118900 + 820 = 119720
Step 147: 119720 + 820 = 120540
Step 148: 120540 + 820 = 121360
Step 149: 121360 + 820 = 122180
Step 150: 122180 + 820 = 123000
Step 151: 123000 + 820 = 123820
Step 152: 123820 + 820 = 124640
Step 153: 124640 + 820 = 125460
Step 154: 125460 + 820 = 126280
Step 155: 126280 + 820 = 127100
Step 156: 127100 + 820 = 127920
Step 157: 127920 + 820 = 128740
Step 158: 128740 + 820 = 129560
Step 159: 129560 + 820 = 130380
Step 160: 130380 + 820 = 131200
Step 161: 131200 + 820 = 132020
Step 162: 132020 + 820 = 132840
Step 163: 132840 + 820 = 133660
Step 164: 133660 + 820 = 134480
Step 165: 134480 + 820 = 135300
Step 166: 135300 + 820 = 136120
Step 167: 136120 + 820 = 136940
Step 168: 136940 + 820 = 137760
Step 169: 137760 + 820 = 138580
Step 170: 138580 + 820 = 139400
Step 171: 139400 + 820 = 140220
Step 172: 140220 + 820 = 141040
Step 173: 141040 + 820 = 141860
Step 174: 141860 + 820 = 142680
Step 175: 142680 + 820 = 143500
Step 176: 143500 + 820 = 144320
Step 177: 144320 + 820 = 145140
Step 178: 145140 + 820 = 145960
Step 179: 145960 + 820 = 146780
Step 180: 146780 + 820 = 147600
Step 181: 147600 + 820 = 148420
Step 182: 148420 + 820 = 149240
Step 183: 149240 + 820 = 150060
Step 184: 150060 + 820 = 150880
Step 185: 150880 + 820 = 151700
Step 186: 151700 + 820 = 152520
Step 187: 152520 + 820 = 153340
Step 188: 153340 + 820 = 154160
Step 189: 154160 + 820 = 154980
Step 190: 154980 + 820 = 155800
Step 191: 155800 + 820 = 156620
Step 192: 156620 + 820 = 157440
Step 193: 157440 + 820 = 158260
Step 194: 158260 + 820 = 159080
Step 195: 159080 + 820 = 159900
Step 196: 159900 + 820 = 160720
Step 197: 160720 + 820 = 161540
Step 198: 161540 + 820 = 162360
Step 199: 162360 + 820 = 163180
Step 200: 163180 + 820 = 164000
Step 201: 164000 + 820 = 164820
Step 202: 164820 + 820 = 165640
Step 203: 165640 + 820 = 166460
Step 204: 166460 + 820 = 167280
Step 205: 167280 + 820 = 168100
Step 206: 168100 + 820 = 168920
Step 207: 168920 + 820 = 169740
Step 208: 169740 + 820 = 170560
Step 209: 170560 + 820 = 171380
Step 210: 171380 + 820 = 172200

So, 820*210 = 172200